My husband and I have a 99 Ford F-150 that as of right now has a (flat 4 I think) and we are getting a tow hitch installed. We are looking at buying a vintage airstream (don't know what year yet 60's or 70's). The people at the hitch installation place asked what kind of plug we want installed. We don't know what we will need. The other question is if we just buy some temp brake lights for the trip home will that plug into the flat 4 thing that we have now?
Help! I have no idea what to do.

Welcome to the forums.
You will need a standard 7 pin connector for your airstream. Airstream trailers have brakes, which are not part of a 4 pin configuration. You will also need a brake controller installed in your truck.

Welcom to forums. Glad to see you are purchasing a vitage unit. The person installing your hitch should be able to do all that Richard says you need. On my 71 unit, the 7 pin connector was a Pollock brand and it had round pins. You will need to match the connector that is on the trailer and it may have round pins.
Good luck in your trip home.BobMember Four Corners UnitWBCCI # 10105AIR # 28748

The 4 pin flat will work for temporary tow/brake lights. You may also some extra connector wire, conections, and quick splices to add wire length from the temporary lights to your vehicle. Someplace like Pep Boys or O'Reillys will probably have what you need.

My suggestion would be to ask your installer to provide an industry standard Bargman/Pollack 7-pin blade style connector with a matching trailer end that you can carry in your glove compartment. With a vintage coach, you may find that the coach's wiring is to the unique to Airstream pattern that was used prior to sometime in the 1980s. Wiring the trailer end to match the industry standard wiring on a tow vehicle isn't hard -- I have done it and I do not have great confidence in my electrical wiring capability. For your safety as well as those around you, you will want to have operable trailer brakes.

The four-pin flat should work fine to run temporary tail/turn/brake lights. You can buy temporary lights that attach magnetically. On my vintage Airstream, however, the nice, convenient flat metal surface is the aluminum cover. I don't know about your potential purchase, but the metal rear bumper on mine is a bit narrow for the magnetic bases. It's also important to realize that depending on the length of the Airstream, it can be a long run from the rear of the truck to the rear of the trailer. I have temporary lights on the Overlander and it took a fair amount of wire to go from the new whip (the cord connection the trailer to the truck) to the back end of the trailer. My wiring job was a bit "hither and yon."

If you buy temporary lights, test them before you go. Bring plenty of spare wire, zip ties, duct tape, etc. Don't expect anything in or on the trailer to work. One of the biggest problem areas for wiring, temporary or permanent, is grounding.

Depending on the length of your two, I'm a fan of using an escort vehicle.

WE put in the brake controller so do that lst! We had trouble as we have a BMW suv 5 series and finally called the people who made the brake controller as they all do not work for German cars and they told us which one would work. Happy Airstreaming and the plug worked that came with the 71 Caravel.